不同连作年限对烟草根际土壤微生物区系的影响

Effects of continuous cropping years on soil microbial flora in the tobacco rhizosphere

为探究不同连作年限对烟草根际土壤微生物区系的变化,利用基因多样性测序技术,分析烟草在连作2年、4年和6年时对根际土壤微生物的数量、群落结构以及物种多样性的影响。结果表明:烟草连作年限的增加会导致根际土壤中可培养细菌和放线菌数量的减少,真菌数量的增多。基因测序结果显示,随着烟草连作年限的增加,微生物群落多样性逐渐下降,群落结构发生改变,微生物类别相对丰度的改变可能是造成不同连作年限间真菌群落结构差异性的原因。不同连作年限下烟草根际土壤细菌群落优势菌属的种类变化比较小,而真菌的群落优势菌属种类变化较大。结合群落结构分布图可知烟草连作年限的增加会增加根际土壤中病原微生物、同时减少有益微生物。

In order to explore the effects of different continuous cropping years on soil microbial flora in the tobacco rhizosphere,the effects of two,four and six years of continuous cropping on soil microbial quantity,community structure and diversity in the tobacco rhizosphere were analyzed by the sequencing of gene diversity.The results showed that the number of culturable bacteria and actinomycetes in rhizosphere soil decreased and the number of fungi increased with the increase of continuous cropping years of tobacco.The results of gene sequencing showed that the diversity of the microbial community decreased gradually with the increase of continuous cropping years,and the community structure changed.The structure of the bacterial community in rhizosphere soil differed greatly under vigorous and long-term no-cropping years,and the structure of the fungal community also differed before and during vigorous and long-term transplantation.The relative abundances of microbial species may be responsible for the differences in fungal community structure between different cropping years.The species of the dominant genus of the bacterial community in the rhizosphere soil of the tobacco field changed little during different continuous cropping years,while the species of the dominant genus of the fungal community changed greatly.The results showed the enrichment of pathogenic microorganisms and the decrease of beneficial microorganisms in rhizosphere soil with the increase of continuous cropping years.